Soldering iron



FIG. 1 is a top, front, left side perspective view of the soldering iron;

FIG. 2 is a top, rear, left side perspective view thereof;

FIG. 3 a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is an enlarged front view thereof; and,

FIG. 8 is an enlarged rear elevation view thereof.

The broken lines show portions of the soldering iron which form no part of the claimed design. 

CLAIM The ornamental design for a soldering iron, as shown and described. 